1. Field of the Invention
The present invention relates to a system for controlling the traveling course as well as the starting and stopping of an unattended transport car.
2. Description of the Related Art
In a typical known unattended transport car control system of the type described above, markers are provided at every turning point and every stop point along a predetermined traveling course of an unattended transport car. The markers are detected by means of an optical sensor mounted on the car, and determinations as to forward or backward movement, right or left turns and stopping or proceeding are made in accordance with a program that supervises movement of the unattended transport car.
The prior systems, however, suffer from several problems. For instance, the markers must be disposed with a high degree of accuracy because of the required positional relationship between the markers and the sensing thereof by the optical sensor mounted on the unattended transport car.
Also, the size of the markers is limited and they cannot carry sufficient information, such as traveling instructions that are to be given to the unattended transport car in advance or at the start of traveling. Moreover, the markers provided along the traveling course are readily contaminated making it likely that the system for controlling the unattended transport car will malfunction.